Many people think that all Androids are equal and it's a race to the bottom where the cheapest vendor wins. This could not be farther from the truth. For me, it all began half-a-year ago, when I bought the Samsung Galaxy S III and was absolutely stunned by it, then exploring and comparing it with other Androids. Now that Google has fired a shot across the bow with its low pricing for the unlocked Nexus 4, where does that leave Samsung and its flagship handset?

I don't think it's clear at all, you mention the Nexus 4 at least 3 times by my count, including in your lead paragraph. Furthermore you often refer to 'the nexus' without specifying whether you mean the galaxy nexus or the nexus 4 in that specific instance.

Now that Google has fired a shot across the bow with its low pricing for the unlocked Nexus 4, where does that leave Samsung and its flagship handset?

You seem to be comparing the S3 against the Galaxy Nexus, the Nexus 4 and some nebulous group of 'chinese phones'. You pick and chose which phone to compare the S3 against for each point to give the best arbitrary score to the S3. Comparing the S2 to the Galaxy Nexus and the S3 to the Nexus 4 are probably more fair comparisons, and undisclosed 'chinese phones' should probably be left out entirely.